Winter's Fortress | The Alps

In the second and final part of NATURE's miniseries "The Alps," experience the hostile and bitter cold ecosystems of the Alps, shaped by snow blizzards and avalanches.

A family of marmots prepares for their upcoming hibernation in a den 6 feet underground. As they prepare for their 6-month sleep, marmots dramatically lower their body temperature and survive on their body’s storage of fat and water. They only wake once every 2 weeks to rev up their heartbeat and visit a nearby tunnel used as a toilet.

Among the chamois in the Alps, the mood is tense. It's the mating season and rivaling bucks tax each other. Each buck needs to decide: Attack or retreat.